Nature Watch
By Susan Thurn,
Cable Natural History Museum
One morning this week my husband and I looked outside and saw a cottontail rabbit feeding right outside our window. The little white burst of color we call a tail resembles a cotton ball for which the rabbit is named. The cottontail’s body was covered with a soft pale-gray mixed cinnamon colored fur with black tips. The rabbit living in our backyard was grooming itself, as their fur isn’t waterproof and needs care to keep their hair in healthy condition. Their large, long ears shifted as a satellite dish as they listened to everything around them. All of these observations were made in a few moments, watching this rabbit outside our window.
The sun was not even up yet when we saw our backyard visitor. Cottontail rabbits browse for food at night on grasses and herbs such as clover, dandelions, alfalfa, fruits and vegetables. In winter, their diet consists of the woody parts of bark, twigs, brambles, and buds of birch, oak, basswood, willow, sumac, dogwood and maple trees. Their teeth are adapted for gnawing on plants. Their top incisor teeth keep growing constantly throughout their lives to allow them to keep chewing away at their meals.
Cottontail rabbits live in a variety of habitats from our neighborhoods, orchards, and farms to sparsely wooded or thick brushy areas. They can travel in a range up to eight acres, and can be moving any time of day or night, but mostly during dawn and dusk. They choose areas with good protection and escape routes.
Freeze tag was always one of my favorite games, and it is one that the cottontail rabbit excels at when avoiding predators. Freezing is far more than a game to these rabbits, as they use this technique to avoid predators, avoiding being noticed until the animal gets too close. Then they shoot out like a bolt of lightning, fleeing from their prey with a zigzag pattern, reaching up to 18 miles per hour and leaping up to fifteen feet away in one move. The zigzag movement gives them an advantage as it breaks their scent trail. Sometimes they will also stand on their hind feet to observe predators.
We all know the cottontail rabbit can sometimes be a bit of a scoundrel to us as they chew away our tulips, but they too can bring great enjoyment in our backyards. Be sure to post your own stories on the Nature Watch blog at cablemuseumnaturewatch.blogspot.com
For over 42 years, the Museum has served as a guide and mentor to generations of visitors and residents interested in learning to better appreciate and care for the extraordinary natural resources of the region. The Museum invites you to visit its facility and exhibit, On Lake Owen: The Art of Walter Bohl, in Cable at 13470 County Highway M. Also find us on the web at www.cablemuseum.org to learn more about our exhibits and programs.
Wednesday, November 24, 2010
Thursday, November 18, 2010
Ruffed Grouse
Nature Watch
By Susan Thurn,
Cable Natural History Museum
While walking in the woods this week it happened again. I was meandering along and enjoying the shades of brown and green colors that greet us in the forest this time of year. Suddenly, I was startled and almost jumped out of my skin when a ruffed grouse flushed out of the brush nearby. I enjoy these birds for their beauty, in spite of the scare they often give me. They are difficult to see as they camouflage themselves so perfectly into their surroundings. As they flush out away from me, the sound of their wings beating loudly as they swiftly fly away matches the speed of my startled, crazy heartbeat.
Some fourth graders I know are currently reading the book Hatchet, by Gary Paulsen, which features a ruffed grouse. In the story, Brian Robeson has managed to survive a plane crash in northern Canada, and is surviving this northwoods wilderness with his wits and a hatchet. Brian names the ruffed grouse “foolbirds.” I have to disagree with Brian’s “name,” as ruffed grouse seem to me anything but foolish. The way grouse find food anytime during the year seems very intelligent to me.
In autumn, there is plenty of food available to a ruffed grouse. There are many different fungi, or mushrooms, to choose from, as long as the birds can find them before the red squirrels. Acorns have fallen from trees, and grouse benefit from white-tailed deer who have stomped on the acorns and broken them open to be found and consumed by the birds. The late-ripening berries are for the taking, and its not just the shrubs and other plants we typically think of that have available fruits, but also low growing plants such as rose hips, bunchberry and wild lily of the valley.
In later fall, the ruffed grouse adapts to new food sources as the bird moves from the ground to the trees. Grouse consume the buds of many different trees such as aspen, birch, and chokecherry. It is believed that with the change to higher fiber-filled tree parts, grouse depend more on micro-organisms in their digestive system to aid them in getting nutrients out of their food.
We are fortunate to be able to enjoy the beauty of ruffed grouse in the northwoods. On second thought, perhaps “foolbird” is an appropriate name, because they sure do fool me with their excellent camouflage and ability to hide. Be sure to get outdoors this fall to enjoy looking for grouse in your own back yard.
For over 42 years, the Museum has served as a guide and mentor to generations of visitors and residents interested in learning to better appreciate and care for the extraordinary natural resources of the region. The Museum invites you to visit its facility and exhibit, On Lake Owen: The Art of Walter Bohl, in Cable at 13470 County Highway M. Also find us on the web at www.cablemuseum.org to learn more about our exhibits and programs. Post your own stories on the Nature Watch blog at cablemuseumnaturewatch.blogspot.com.
By Susan Thurn,
Cable Natural History Museum
While walking in the woods this week it happened again. I was meandering along and enjoying the shades of brown and green colors that greet us in the forest this time of year. Suddenly, I was startled and almost jumped out of my skin when a ruffed grouse flushed out of the brush nearby. I enjoy these birds for their beauty, in spite of the scare they often give me. They are difficult to see as they camouflage themselves so perfectly into their surroundings. As they flush out away from me, the sound of their wings beating loudly as they swiftly fly away matches the speed of my startled, crazy heartbeat.
Some fourth graders I know are currently reading the book Hatchet, by Gary Paulsen, which features a ruffed grouse. In the story, Brian Robeson has managed to survive a plane crash in northern Canada, and is surviving this northwoods wilderness with his wits and a hatchet. Brian names the ruffed grouse “foolbirds.” I have to disagree with Brian’s “name,” as ruffed grouse seem to me anything but foolish. The way grouse find food anytime during the year seems very intelligent to me.
In autumn, there is plenty of food available to a ruffed grouse. There are many different fungi, or mushrooms, to choose from, as long as the birds can find them before the red squirrels. Acorns have fallen from trees, and grouse benefit from white-tailed deer who have stomped on the acorns and broken them open to be found and consumed by the birds. The late-ripening berries are for the taking, and its not just the shrubs and other plants we typically think of that have available fruits, but also low growing plants such as rose hips, bunchberry and wild lily of the valley.
In later fall, the ruffed grouse adapts to new food sources as the bird moves from the ground to the trees. Grouse consume the buds of many different trees such as aspen, birch, and chokecherry. It is believed that with the change to higher fiber-filled tree parts, grouse depend more on micro-organisms in their digestive system to aid them in getting nutrients out of their food.
We are fortunate to be able to enjoy the beauty of ruffed grouse in the northwoods. On second thought, perhaps “foolbird” is an appropriate name, because they sure do fool me with their excellent camouflage and ability to hide. Be sure to get outdoors this fall to enjoy looking for grouse in your own back yard.
For over 42 years, the Museum has served as a guide and mentor to generations of visitors and residents interested in learning to better appreciate and care for the extraordinary natural resources of the region. The Museum invites you to visit its facility and exhibit, On Lake Owen: The Art of Walter Bohl, in Cable at 13470 County Highway M. Also find us on the web at www.cablemuseum.org to learn more about our exhibits and programs. Post your own stories on the Nature Watch blog at cablemuseumnaturewatch.blogspot.com.
Wednesday, November 10, 2010
Fox Sparrow
Nature Watch
By Susan Thurn,
Cable Natural History Museum
The bird feeders at my parent’s house are still busy in spite of the many migrant birds that have left us for a while. A few glances at the feeder show the less colorful winter plumage of the goldfinch, the slate-colored juncos, chickadees, downy and hairy woodpeckers, white and red-breasted nuthatches, blue jays, cardinals, mourning doves, white-throated and fox sparrows. It was the fox sparrows that recently caught my eye, and ears. A larger sparrow, fox sparrows are bright rust-colored on the tail and wing. There are red, thick streaks on the breast, and reddish streaks on a gray colored back with faint white wingbars. Their lower mandible is colored pink to yellow-orange. These sparrows are a striking bird, and have some additionally interesting behaviors.
Fox sparrows most appealing behaviors are ones to hear, rather than see. They scratch through leaves through insects and seeds, and make so much noise they sound like a larger animal. These noticeable actions come from a vigorous double-scratching as the fox sparrow kicks backward in the litter with a two-footed jump-kick motion as they work to uncover food. This same foraging behavior unfortunately makes them vulnerable to cats and other predators.
The main food choices of fox sparrows are seeds from grasses and a plant called smartweed. They will eat berries as well. During warmer seasons, they also eat insects and feed them to their young. When nesting, adults are known to perform a broken-wing display to lure potential threats away from the nest.
Be sure to enjoy the fox sparrows around your own feeders, birds which are collectively known as a “den,” or “slyness” of sparrows. Enjoy them while you can though, as they spend our winters in the warmer climates of North America. Their migration this season began in early October and by mid-November, only the last few will remain in our neck of the woods. Watch and listen for this last glimpse of color and sound as they scratch around the fall leaves of our northwoods backyards.
For over 42 years, the Museum has served as a guide and mentor to generations of visitors and residents interested in learning to better appreciate and care for the extraordinary natural resources of the region. The Museum invites you to visit its facility and exhibit, On Lake Owen: The Art of Walter Bohl, in Cable at 13470 County Highway M. Also find us on the web at www.cablemuseum.org to learn more about our exhibits and programs. Post your own stories on the Nature Watch blog at cablemuseumnaturewatch.blogspot.com.
By Susan Thurn,
Cable Natural History Museum
The bird feeders at my parent’s house are still busy in spite of the many migrant birds that have left us for a while. A few glances at the feeder show the less colorful winter plumage of the goldfinch, the slate-colored juncos, chickadees, downy and hairy woodpeckers, white and red-breasted nuthatches, blue jays, cardinals, mourning doves, white-throated and fox sparrows. It was the fox sparrows that recently caught my eye, and ears. A larger sparrow, fox sparrows are bright rust-colored on the tail and wing. There are red, thick streaks on the breast, and reddish streaks on a gray colored back with faint white wingbars. Their lower mandible is colored pink to yellow-orange. These sparrows are a striking bird, and have some additionally interesting behaviors.
Fox sparrows most appealing behaviors are ones to hear, rather than see. They scratch through leaves through insects and seeds, and make so much noise they sound like a larger animal. These noticeable actions come from a vigorous double-scratching as the fox sparrow kicks backward in the litter with a two-footed jump-kick motion as they work to uncover food. This same foraging behavior unfortunately makes them vulnerable to cats and other predators.
The main food choices of fox sparrows are seeds from grasses and a plant called smartweed. They will eat berries as well. During warmer seasons, they also eat insects and feed them to their young. When nesting, adults are known to perform a broken-wing display to lure potential threats away from the nest.
Be sure to enjoy the fox sparrows around your own feeders, birds which are collectively known as a “den,” or “slyness” of sparrows. Enjoy them while you can though, as they spend our winters in the warmer climates of North America. Their migration this season began in early October and by mid-November, only the last few will remain in our neck of the woods. Watch and listen for this last glimpse of color and sound as they scratch around the fall leaves of our northwoods backyards.
For over 42 years, the Museum has served as a guide and mentor to generations of visitors and residents interested in learning to better appreciate and care for the extraordinary natural resources of the region. The Museum invites you to visit its facility and exhibit, On Lake Owen: The Art of Walter Bohl, in Cable at 13470 County Highway M. Also find us on the web at www.cablemuseum.org to learn more about our exhibits and programs. Post your own stories on the Nature Watch blog at cablemuseumnaturewatch.blogspot.com.
Wednesday, November 3, 2010
Fall Leaf Decomposition
Nature Watch
By Susan Thurn,
Cable Natural History Museum
“Scrunch,” “scrunch” went the crunch of dry leaves under my feet. The brown, dead leaves have been a delight for many that love to walk through leaf litter while kicking up fall leaves. For others, the leaves are perhaps part of a fall routine as people rake them from their lawns. For nature, decomposition is the natural process for leaves as they fall to the ground, creating new building blocks of life recycled over again. Right now in the forest this recycling is a job filled by invertebrates, fungi and bacteria.
Decomposition of leaves occurs through many different means. Invertebrates and earthworms break leaves into smaller fragments. This process allows the leaf pieces to have more surface area to support the next step of decomposition, bacteria and fungi. Rain also filters through the leaves, dissolving chemicals and nutrients. Bacteria grow better when the leaf fragments are smaller. The organic matter is broken down to carbon, nitrogen and other minerals.
Certain species of fungi also aide with the decomposition of leaves. Fungi hyphae fibers spread through dead leaf litter just under the forest floor, extracting nutrients the fungi need to survive. These hyphae develop into matted carpets that we sometimes see when leaf litter is moved. The speed at which decomposition occurs depends on moisture, temperature and composition of the leaf matter. Lower temperatures make decomposition occur more slowly. Leaves with low nitrogen also slow decay because the fungi cannot gain enough nitrogen from the organic matter to make necessary proteins. Lower oxygen environments also slow decomposition.
Waste not, want not is the perfect description of our leaf decomposers. Without them, nitrogen and other nutrients would be locked in the dead leaves, not leaving enough for living plants and their needs in making new leaves and seeds. Those bacteria and mushrooms are such “fun-guys!”
For over 42 years, the Museum has served as a guide and mentor to generations of visitors and residents interested in learning to better appreciate and care for the extraordinary natural resources of the region. The Museum invites you to visit its facility and exhibit, On Lake Owen: The Art of Walter Bohl, in Cable at 13470 County Highway M. Also find us on the web at www.cablemuseum.org to learn more about our exhibits and programs. Post your own stories on the Nature Watch blog at cablemuseumnaturewatch.blogspot.com.
By Susan Thurn,
Cable Natural History Museum
“Scrunch,” “scrunch” went the crunch of dry leaves under my feet. The brown, dead leaves have been a delight for many that love to walk through leaf litter while kicking up fall leaves. For others, the leaves are perhaps part of a fall routine as people rake them from their lawns. For nature, decomposition is the natural process for leaves as they fall to the ground, creating new building blocks of life recycled over again. Right now in the forest this recycling is a job filled by invertebrates, fungi and bacteria.
Decomposition of leaves occurs through many different means. Invertebrates and earthworms break leaves into smaller fragments. This process allows the leaf pieces to have more surface area to support the next step of decomposition, bacteria and fungi. Rain also filters through the leaves, dissolving chemicals and nutrients. Bacteria grow better when the leaf fragments are smaller. The organic matter is broken down to carbon, nitrogen and other minerals.
Certain species of fungi also aide with the decomposition of leaves. Fungi hyphae fibers spread through dead leaf litter just under the forest floor, extracting nutrients the fungi need to survive. These hyphae develop into matted carpets that we sometimes see when leaf litter is moved. The speed at which decomposition occurs depends on moisture, temperature and composition of the leaf matter. Lower temperatures make decomposition occur more slowly. Leaves with low nitrogen also slow decay because the fungi cannot gain enough nitrogen from the organic matter to make necessary proteins. Lower oxygen environments also slow decomposition.
Waste not, want not is the perfect description of our leaf decomposers. Without them, nitrogen and other nutrients would be locked in the dead leaves, not leaving enough for living plants and their needs in making new leaves and seeds. Those bacteria and mushrooms are such “fun-guys!”
For over 42 years, the Museum has served as a guide and mentor to generations of visitors and residents interested in learning to better appreciate and care for the extraordinary natural resources of the region. The Museum invites you to visit its facility and exhibit, On Lake Owen: The Art of Walter Bohl, in Cable at 13470 County Highway M. Also find us on the web at www.cablemuseum.org to learn more about our exhibits and programs. Post your own stories on the Nature Watch blog at cablemuseumnaturewatch.blogspot.com.
Thursday, October 28, 2010
Turning
Nature Watch
By Susan Thurn
Cable Natural History Museum
Chilly fall days give us a warning that winter is coming, and in response plants and animals (including we humans) adjustment accordingly.
The changing of the season also affects the behavior of bodies of water. You may have heard people referring to lakes “turning” this time of year, and wondered what that means.
It’s a twice-yearly phenomenon related to water and air temperature—here’s how it works: In late summer, lake surface waters reach their annual maximum temperatures. Deeper waters are cooler—in many lakes, there is a definite stratification or layering of water temperatures that you would feel if you were swimming on the surface and then dove down deep. The warmest, least dense waters lie on top; water temperature decreases with depth, reaching its minimum temperature at the greatest lake depths.
In the summer, a deep lake will have three layers in the water column: the upper, warmest water (the epilimnion); a thin middle layer, where temperatures rapidly decrease (the thermocline or mesolimnion); and the deepest, coldest water (hypolimnion).
In autumn, cooler air temperatures and diminished hours of sunlight result in a loss of heat from the lake’s upper water layer. As these waters cool, they become more dense and when they reach about 50 degrees F, they sink into the middle layer below, erasing the temperature stratification that had developed during summer.
Eventually, all the lake water reaches a uniform temperature, and surface winds then mix all the water. When the winds are strong and fairly constant in direction for an extended time, they establish a water circulation pattern—as surface waters are blown downwind, waters from below must rise along the upwind shore to replace those waters pushed across the surface. To complete the circuit, the downwind shore surface waters, piled up by the wind, sink to replace the rising bottom waters.
In time, the resulting circulations will completely overturn and mix all the lake’s water—hence “fall turning.” The phenomenon can at times produce a rotten-egg odor, since the deep waters, which are low in oxygen and high in sulphur, rise to the surface and release sulphurous gases into the air. The turnover also mixes atmospheric oxygen into the lake water, replenishing the oxygen in deep waters and allowing fish to return to the depths where many will spend the winter.
Of course, after the fall turning cools the lakewater and as winter approaches, surface waters approach the freezing mark. Unlike most compounds, water reaches its maximum density as a liquid just before becoming a solid. Under normal conditions, freshwater is most dense at 39 degrees F, and ice, being less dense than liquid water, floats. So as lake waters cool, they sink when they reach 39 degrees. Colder water remains above, and is eventually covered with ice.
In the spring, the cycle happens again in reverse. Ice cover melts, and cold surface waters warm until they reach the temperatures of the bottom waters. Winds blowing over the lake again set up a full circulation system; as warming continues, the three water layers again become established, and a full turn of the cycle is complete.
For over 42 years, the Museum has served as a guide and mentor to generations of visitors and residents interested in learning to better appreciate and care for the extraordinary natural resources of the region. The Museum invites you to visit its facility and new exhibit, On Lake Owen: The Art of Walter Bohl, in Cable at 13470 County Highway M. Also find us on the web at www.cablemuseum.org to learn more about our exhibits and programs. Post your own stories on the Nature Watch blog at cablemuseumnaturewatch.blogspot.com.
By Susan Thurn
Cable Natural History Museum
Chilly fall days give us a warning that winter is coming, and in response plants and animals (including we humans) adjustment accordingly.
The changing of the season also affects the behavior of bodies of water. You may have heard people referring to lakes “turning” this time of year, and wondered what that means.
It’s a twice-yearly phenomenon related to water and air temperature—here’s how it works: In late summer, lake surface waters reach their annual maximum temperatures. Deeper waters are cooler—in many lakes, there is a definite stratification or layering of water temperatures that you would feel if you were swimming on the surface and then dove down deep. The warmest, least dense waters lie on top; water temperature decreases with depth, reaching its minimum temperature at the greatest lake depths.
In the summer, a deep lake will have three layers in the water column: the upper, warmest water (the epilimnion); a thin middle layer, where temperatures rapidly decrease (the thermocline or mesolimnion); and the deepest, coldest water (hypolimnion).
In autumn, cooler air temperatures and diminished hours of sunlight result in a loss of heat from the lake’s upper water layer. As these waters cool, they become more dense and when they reach about 50 degrees F, they sink into the middle layer below, erasing the temperature stratification that had developed during summer.
Eventually, all the lake water reaches a uniform temperature, and surface winds then mix all the water. When the winds are strong and fairly constant in direction for an extended time, they establish a water circulation pattern—as surface waters are blown downwind, waters from below must rise along the upwind shore to replace those waters pushed across the surface. To complete the circuit, the downwind shore surface waters, piled up by the wind, sink to replace the rising bottom waters.
In time, the resulting circulations will completely overturn and mix all the lake’s water—hence “fall turning.” The phenomenon can at times produce a rotten-egg odor, since the deep waters, which are low in oxygen and high in sulphur, rise to the surface and release sulphurous gases into the air. The turnover also mixes atmospheric oxygen into the lake water, replenishing the oxygen in deep waters and allowing fish to return to the depths where many will spend the winter.
Of course, after the fall turning cools the lakewater and as winter approaches, surface waters approach the freezing mark. Unlike most compounds, water reaches its maximum density as a liquid just before becoming a solid. Under normal conditions, freshwater is most dense at 39 degrees F, and ice, being less dense than liquid water, floats. So as lake waters cool, they sink when they reach 39 degrees. Colder water remains above, and is eventually covered with ice.
In the spring, the cycle happens again in reverse. Ice cover melts, and cold surface waters warm until they reach the temperatures of the bottom waters. Winds blowing over the lake again set up a full circulation system; as warming continues, the three water layers again become established, and a full turn of the cycle is complete.
For over 42 years, the Museum has served as a guide and mentor to generations of visitors and residents interested in learning to better appreciate and care for the extraordinary natural resources of the region. The Museum invites you to visit its facility and new exhibit, On Lake Owen: The Art of Walter Bohl, in Cable at 13470 County Highway M. Also find us on the web at www.cablemuseum.org to learn more about our exhibits and programs. Post your own stories on the Nature Watch blog at cablemuseumnaturewatch.blogspot.com.
Wednesday, October 20, 2010
Northern Pike
Nature Watch
By Susan Thurn,
Cable Natural History Museum
They were trolling the waters for a big fish, the musky. “Fish on,” were the words heard from the boat as the sound floated across the water. It was a decent sized fish, but it wasn’t a musky. Instead, it was the struggle of a northern pike that was brought into the boat. This tooth-filled mouth earns its place as the second largest predator fish in northern Wisconsin.
Northern Pike have a duck bill shaped long snout that is lined with sharp canine type teeth. Their olive-green upper sides are marked with longitudinal rows of yellow spots. This “handsome-looking” fish can live for more than 20 years.
The northern pike is a cool-water species whose habitat is usually warm, slow, and shallow, heavily vegetated rivers or the weedy bays of lakes. They also can be found in cold, clear, rocky water bodies. A solitary and territorial fish, northern pike ambush their predators, laying in wait at the edge of weed beds to dart out, attacking with surprising speed. Young northern pike feed on immature aquatic insects and then fish. Adults will eat fish, crayfish, ducklings, muskrats, frogs, leeches or mice. Northern pike are known for being less particular about their food choices. They will even eat younger pike fish, making it critical for the young pike to find safe shelter among vegetation. Northerns typically catch their prey sideways, immobilizing their prey with the backward pointing teeth, and then turning the prey headfirst so they can swallow it. Younger pike have been found dead having choked on a pike of a similar size.
It may be that the catch and release fishing of my family has been the best way to catch glimpses of a northern pike. A swirl or swish at the water’s surface makes me take a second look, hoping for a view of a fish. These fish are just one of the many enjoyable experiences we can look forward to experiencing in our northwoods back yard.
For over 42 years, the Museum has served as a guide and mentor to generations of visitors and residents interested in learning to better appreciate and care for the extraordinary natural resources of the region. The Museum invites you to visit its facility and new exhibit, On Lake Owen: The Art of Walter Bohl, in Cable at 13470 County Highway M. Also find us on the web at www.cablemuseum.org to learn more about our exhibits and programs. Post your own stories on the Nature Watch blog at cablemuseumnaturewatch.blogspot.com.
By Susan Thurn,
Cable Natural History Museum
They were trolling the waters for a big fish, the musky. “Fish on,” were the words heard from the boat as the sound floated across the water. It was a decent sized fish, but it wasn’t a musky. Instead, it was the struggle of a northern pike that was brought into the boat. This tooth-filled mouth earns its place as the second largest predator fish in northern Wisconsin.
Northern Pike have a duck bill shaped long snout that is lined with sharp canine type teeth. Their olive-green upper sides are marked with longitudinal rows of yellow spots. This “handsome-looking” fish can live for more than 20 years.
The northern pike is a cool-water species whose habitat is usually warm, slow, and shallow, heavily vegetated rivers or the weedy bays of lakes. They also can be found in cold, clear, rocky water bodies. A solitary and territorial fish, northern pike ambush their predators, laying in wait at the edge of weed beds to dart out, attacking with surprising speed. Young northern pike feed on immature aquatic insects and then fish. Adults will eat fish, crayfish, ducklings, muskrats, frogs, leeches or mice. Northern pike are known for being less particular about their food choices. They will even eat younger pike fish, making it critical for the young pike to find safe shelter among vegetation. Northerns typically catch their prey sideways, immobilizing their prey with the backward pointing teeth, and then turning the prey headfirst so they can swallow it. Younger pike have been found dead having choked on a pike of a similar size.
It may be that the catch and release fishing of my family has been the best way to catch glimpses of a northern pike. A swirl or swish at the water’s surface makes me take a second look, hoping for a view of a fish. These fish are just one of the many enjoyable experiences we can look forward to experiencing in our northwoods back yard.
For over 42 years, the Museum has served as a guide and mentor to generations of visitors and residents interested in learning to better appreciate and care for the extraordinary natural resources of the region. The Museum invites you to visit its facility and new exhibit, On Lake Owen: The Art of Walter Bohl, in Cable at 13470 County Highway M. Also find us on the web at www.cablemuseum.org to learn more about our exhibits and programs. Post your own stories on the Nature Watch blog at cablemuseumnaturewatch.blogspot.com.
Wednesday, October 13, 2010
Slugs
Nature Watch
By Susan Thurn,
Cable Natural History Museum
“I’ve been slimed!” That’s the comment that came out of my mouth this week as I discovered a host of slugs underneath the log I had just lifted. With the rain we have had this summer and fall, the slugs seem to be more easily observed. It is not just their slug trails that are fascinating to learn about.
Slugs and snails are related and are called gastropods. Like other land snails, most slugs have two pairs of 'feelers' or tentacles on their head. The upper pair senses light while the lower pair is their sense of smell. When disturbed, they retract either pair, and if damaged, they can re-grow the tentacles. Slugs move through muscular contractions on the underside of their foot. Slugs feed on plant materials with a rasping, specialized mouthpart. Slugs can stretch their bodies to 20 times their normal length, allowing them to squeeze through the tiniest spaces to get to their food. They produce mucus to assist them with movement. The mucus secreted by their foot contains fibers to keep the slug from slipping down steep surfaces. Their bodies are made of mostly water, so their soft tissues need to always stay moist. A thicker mucus coats their entire body for protection from elements and predators. When attacked, slugs can contract their body, making their bodies more compact, which when combined with the slippery mucus, makes it difficult to grab. The mucus also is distasteful as a deterrent. For us, just touching this slime can be a deterrent!
The slime trail slugs leave behind has other effects than just assisting with transportation. A slug can use its own trail again and again to find its way around. Other slugs recognize the trail as their own species, leading to success in finding a mate. The trails can also be used by other slugs to find a good plant food source. Carnivorous slugs will also use the trails to find other slugs as a meal. Finally, many slugs will secrete slime cords to lower themselves to the ground.
Slugs feed mostly at night, seeking shelter during the day in soil or under leafy debris. They become more inactive during dry, hot weather, and more active after rain because of the moisture. In drier conditions, they hide in damp places such as under leaves, tree bark, logs, rocks, and man-made structures to retain their body moisture.
Fall is a great time for slugs. This time of year they lay up to fifty eggs in the soil, where the eggs will wait through winter or sometimes for years until moisture conditions are right. Their egg clusters look like colorless jelly. During the winter, some slug species overwinter in hibernation under ground while with other species, the adults die in the autumn.
To some gardeners slugs are considered to be pests because of the destruction they can create in our gardens. However, many slug species play an important role in our ecosystem by eating decaying plant matter. Some slugs eat other slugs and snails, earthworms, or even carrion. They are also food to snakes, salamanders, turtles, birds, toads and even humans. Explore your own back yard, as you never know what slime trails you might run into!
For over 42 years, the Museum has served as a guide and mentor to generations of visitors and residents interested in learning to better appreciate and care for the extraordinary natural resources of the region. The Museum invites you to visit its facility and new exhibit, On Lake Owen: The Art of Walter Bohl, in Cable at 13470 County Highway M. Also find us on the web at www.cablemuseum.org to learn more about our exhibits and programs. Post your own stories on the Nature Watch blog at cablemuseumnaturewatch.blogspot.com.
By Susan Thurn,
Cable Natural History Museum
“I’ve been slimed!” That’s the comment that came out of my mouth this week as I discovered a host of slugs underneath the log I had just lifted. With the rain we have had this summer and fall, the slugs seem to be more easily observed. It is not just their slug trails that are fascinating to learn about.
Slugs and snails are related and are called gastropods. Like other land snails, most slugs have two pairs of 'feelers' or tentacles on their head. The upper pair senses light while the lower pair is their sense of smell. When disturbed, they retract either pair, and if damaged, they can re-grow the tentacles. Slugs move through muscular contractions on the underside of their foot. Slugs feed on plant materials with a rasping, specialized mouthpart. Slugs can stretch their bodies to 20 times their normal length, allowing them to squeeze through the tiniest spaces to get to their food. They produce mucus to assist them with movement. The mucus secreted by their foot contains fibers to keep the slug from slipping down steep surfaces. Their bodies are made of mostly water, so their soft tissues need to always stay moist. A thicker mucus coats their entire body for protection from elements and predators. When attacked, slugs can contract their body, making their bodies more compact, which when combined with the slippery mucus, makes it difficult to grab. The mucus also is distasteful as a deterrent. For us, just touching this slime can be a deterrent!
The slime trail slugs leave behind has other effects than just assisting with transportation. A slug can use its own trail again and again to find its way around. Other slugs recognize the trail as their own species, leading to success in finding a mate. The trails can also be used by other slugs to find a good plant food source. Carnivorous slugs will also use the trails to find other slugs as a meal. Finally, many slugs will secrete slime cords to lower themselves to the ground.
Slugs feed mostly at night, seeking shelter during the day in soil or under leafy debris. They become more inactive during dry, hot weather, and more active after rain because of the moisture. In drier conditions, they hide in damp places such as under leaves, tree bark, logs, rocks, and man-made structures to retain their body moisture.
Fall is a great time for slugs. This time of year they lay up to fifty eggs in the soil, where the eggs will wait through winter or sometimes for years until moisture conditions are right. Their egg clusters look like colorless jelly. During the winter, some slug species overwinter in hibernation under ground while with other species, the adults die in the autumn.
To some gardeners slugs are considered to be pests because of the destruction they can create in our gardens. However, many slug species play an important role in our ecosystem by eating decaying plant matter. Some slugs eat other slugs and snails, earthworms, or even carrion. They are also food to snakes, salamanders, turtles, birds, toads and even humans. Explore your own back yard, as you never know what slime trails you might run into!
For over 42 years, the Museum has served as a guide and mentor to generations of visitors and residents interested in learning to better appreciate and care for the extraordinary natural resources of the region. The Museum invites you to visit its facility and new exhibit, On Lake Owen: The Art of Walter Bohl, in Cable at 13470 County Highway M. Also find us on the web at www.cablemuseum.org to learn more about our exhibits and programs. Post your own stories on the Nature Watch blog at cablemuseumnaturewatch.blogspot.com.
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